Actuator plate partitioning and control devices and methods

ABSTRACT

Devices and methods of operating partitioned actuator plates to obtain a desirable shape of a movable component of a micro-electro-mechanical system (MEMS) device. The subject matter described herein can in some embodiments include a micro-electro-mechanical system (MEMS) device including a plurality of actuation electrodes attached to a first surface, where each of the one or more actuation electrode being independently controllable, and a movable component spaced apart from the first surface and movable with respect to the first surface. Where the movable component further includes one or more movable actuation electrodes spaced apart from the plurality of fixed actuation electrodes.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation patent application of U.S.patent application Ser. No. 14/216,213, filed Mar. 17, 2014, whichclaims the benefit of U.S. Provisional Patent Application Ser. No.61/792,201, filed Mar. 15, 2013, the disclosures of which areincorporated herein by reference in their entireties.

TECHNICAL FIELD

The subject matter disclosed herein relates generally to operations of amicro-electro-mechanical system (MEMS) device. More particularly, thesubject matter disclosed herein relates to devices and methods ofactuating the movement of a movable component of a MEMS device.

BACKGROUND

Micro-electro-mechanical systems (MEMS) technology has been widely usedin the wireless communication industry to improve performance ofexisting devices based on structure or operational principles. Forexample, a MEMS tunable capacitor can be developed using micromachiningtechnology and used as a part of a voltage controlled oscillator. As anRF component, a MEMS tunable capacitor can be micro-machined on siliconsubstrates and be integrated with active circuit components usingmodified integrated circuit fabrication processes. MEMS tunablecapacitors can have the advantages of lower losses and potentiallygreater tuning range compared to solid-state varactors. Theinterconnection loss and noise can also be less than those of usingoff-chip RF components. However, tuning range of a MEMS tunablecapacitor can be limited by factors such as parasitic capacitances. Inaddition, device performance can suffer from factors such as adhesionbetween movable components and the substrate.

Accordingly, it would be desirable for devices, and methods for MEMSdevices to produce a wider tuning range and improve device reliability.

SUMMARY

In accordance with this disclosure, micro-electro-mechanical system(MEMS) devices with partitioned actuation plates and methods for theoperation thereof are provided. In one aspect, a configuration for aMEMS device is provided. The MEMS device can comprise a plurality ofactuation electrodes attached to a first surface, wherein each of theone or more actuation electrode being independently controllable. TheMEMS device can further comprise a movable component spaced apart fromthe first surface and movable with respect to the first surface, whereinthe movable component can comprise one or more movable actuationelectrodes spaced apart from the plurality of fixed actuationelectrodes.

In another aspect, another configuration for a MEMS device is provided.The MEMS device can comprise a first plurality of fixed actuationelectrodes attached to a first surface, wherein each of the plurality offixed actuation electrode is independently controllable. The MEMS devicecan further comprise a second plurality of fixed actuation electrodesattached to a second surface, wherein each of the plurality of actuationelectrode is independently controllable, and at least one actuationelectrode attached to a movable component, wherein the movable componentis positioned between the first surface and the second surface andmovable with respect to the first or second surface.

In yet another aspect, a method for adjusting a shape of a movablecomponent of a MEMS device is provided. The method can comprisedeflecting a movable component by selectively actuating a first subsetof a plurality of fixed actuation electrodes using one or moreindependently controllable voltage driver, wherein the fixed actuationelectrodes are independently controllable and attached to a first orsecond surface. The method can further comprise selectively actuating asecond subset of the plurality of the fixed actuation electrodesdifferent than the first subset to adjust a shape of the movablecomponent.

As used herein, the terms actuating an electrode or electrode actuationrefer to supplying a bias voltage to an electrode to actuate or energizethe electrode.

Although some of the aspects of the subject matter disclosed herein havebeen stated hereinabove, and which are achieved in whole or in part bythe presently disclosed subject matter, other aspects will becomeevident as the description proceeds when taken in connection with theaccompanying drawings as best described hereinbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the present subject matter will be morereadily understood from the following detailed description which shouldbe read in conjunction with the accompanying drawings that are givenmerely by way of explanatory and non-limiting example, and in which:

FIGS. 1A and 1B are side views of a MEMS device comprising independentlycontrollable actuation electrodes according to various embodiments ofthe presently disclosed subject matter;

FIGS. 2A to 2E are side views of a MEMS device comprising a movablecomponent under various actuated states according to various embodimentsof the presently disclosed subject matter;

FIGS. 3A to 3D are side views of a MEMS device comprising at least onestandoff bump and under various actuated states according to anembodiment of the presently disclosed subject matter;

FIG. 4 is a side view of a MEMS device comprising one or more standoffpivots in an un-actuated state in accordance to embodiments of thepresently disclosed subject matter;

FIG. 5 is a side view of a MEMS device comprising one or more standoffpivots in an actuated state in accordance to embodiments of thepresently disclosed subject matter;

FIG. 6 is a side view of a MEMS device comprising one or more standoffpivots in another actuated state in accordance to embodiments of thepresently disclosed subject matter;

FIGS. 7A to 7C are side views of a MEMS device comprising a movablecomponent positioned between two surfaces and under various actuatedstates in accordance to embodiments of the presently disclosed subjectmatter;

FIGS. 8A to 8C are side views of a MEMS device with independentlycontrollable actuation electrodes fixed to a first and a second surfaceand under various actuated states in accordance to embodiments of thepresently disclosed subject matter; and

FIG. 9A to 9C are side views of MEMS device comprising one or morestandoff pivots and one or more standoff bumps and under variousactuated states in accordance to embodiments of the presently disclosedsubject matter.

DETAILED DESCRIPTION

The present subject matter provides devices and methods for MEMSvariable capacitors. In one aspect, the present subject matter providesconfigurations for MEMS variable capacitors that exhibit improvedcycling lifetimes, allow improved capacitor contact, enable a snappull-in characteristic that can be desirable for stable two-stateoperation, and reduce actuator stiction, contact forces, charging,breakdown, cycling, and/or hold down. To achieve these benefits, thepresent subject matter is directed to MEMS devices with independentlycontrollable actuation electrodes and methods for controlling theactuation electrodes for adjusting a shape of a movable component. Insome embodiments, the present subject matter provides a multi-statetunable capacitor in which individual bits (e.g., ⅛, ¼, ½ pF) can beintegrated into a single, multi-state switch. This tunable capacitor caninclude a movable component with actuator plates fixed onto thecomponent's surfaces. The actuator plates can be partitioned intomultiple sections along the length of the device. The partitionedactuator sections can function as actuation electrodes and vary insizes. For example, actuator electrodes close to the edges of themovable component can be smaller in size than the other actuatorelectrodes. Furthermore, the actuation electrodes can be sequentiallybiased to release or partially release a capacitor section to achieve adesired capacitance value. For example, one or more of the actuationelectrodes can be selectively actuated to achieve a variety of capacitorstates. To control this selective actuation, multiple high voltagedrivers can be provided to bias the actuation electrodes, and a drivercontroller with multiple output terminals can be provided to control theactuation sequences.

In some embodiments, a subset of actuation electrodes can be selectivelyactuated to achieve an optimized static beam shape for a desiredcapacitance. For example, the plurality of actuation electrodes can beselectively energized to deflect the movable component relative to afirst or second surface to maximize the capacitance of the device byoptimally flattening the capacitor plate or electrode.

In some embodiments, the partitioned actuator plate configuration canfurther be used to reduce hold down voltage and/or increase hold downlifetime by using area control to maintain the beam in an actuated staterather than using voltage control. For example, all actuation electrodescan be driven or actuated during a pull-in phase, but once the movablecomponent has moved to an actuated (e.g., closed) position, feweractuation electrodes need to be actuated to hold down the movablecomponent. As such, hold down and pull in of the movable component canboth be performed at a reduced voltage compared to conventional systems.Furthermore, actuation electrodes that are grounded (e.g., zero voltagestate) can be specifically selected to be those close to a fixedcapacitor plate to function as a shield ring against leakage currents,which can help preventing capacitor plate charging.

In some embodiments, a capacitor plate can be configured to function asan actuation electrode. The capacitor plate can assist with the initialpull in, thereby allowing the movable component to be smaller and/orstiffer, and the capacitor plate can be grounded during hold down toavoid charging.

In some embodiments, stiction can be reduced by sequentially actuate theactuation electrodes to achieve a leveraged breaking force. For example,actuation electrodes can be position across the width and/or length ofthe device. When lifting the movable component away from the firstsurface (i.e., substrate), actuation electrodes on a first side of thesubstrate can be released before releasing actuation electrodes on anopposing second side of the substrate to effectively rocking the movablecomponent away from the substrate.

In some embodiments, one or more standoff bumps can be positioned on oneor more actuation electrodes. In this configuration, actuationelectrodes on one side of a standoff bump can be actuated to pivot themovable component such that a force is exerted to lift the movablecomponent away from actuation electrodes on other side of the standoffbump. This pivoting can provide a number of advantages to the operationof the device. For example, the actuation electrodes can be actuated forincreasing a self-actuation release voltage V_(sar) for high power hotswitching. It also operates to increase the opening force and thusreduces or eliminates sticking due to charging or surface adhesion. Inaddition, the present subject matter can be configured to activelyincrease an average distance between the fixed capacitive electrode andthe movable capacitive electrode D_(avg) to raise a self-actuationvoltage V_(sar) and/or to lower a minimum capacitance C_(min) the fixedcapacitive electrode and the movable capacitive electrode.

In yet a further extension of this concepts disclosed herein, actuationelectrodes on either side of a standoff pivot can be operated in anantagonistic manner to support a capacitance on the substrate and lid ofa 2-pole switch or to support an antagonistic balance for increasedself-actuation voltage V_(sar). For example, antagonistic operation ofthe actuation electrodes can result in a movable capacitive plate (i.e.,on the movable component) being movable to a position that is fartherfrom the fixed capacitive plate than when in a neutral state.

FIG. 1A illustrates a side view of a first exemplary configuration of aMEMS device, generally designated 100, comprising individual actuationelectrodes according to various embodiments of the presently disclosedsubject matter. As illustrated in FIG. 1A, device 100 can include one ormore actuator plates partitioned into a plurality of independentlycontrollable fixed actuation electrodes 102 ₁-102 _(N) fixed or attachedto a first surface (e.g., substrate 110). In some embodiments, actuationelectrodes 102 ₁-102 _(N) can be electrically coupled to one or morevoltage supply units. For example, a voltage supply unit 104 ₁ can beelectrically coupled to actuation electrode 102 ₁ and configured toprovide a bias voltage, where voltage supply unit 104 ₁ can comprise ahigh voltage driver (e.g., a CMOS device) and a voltage control unit(e.g., binary crowbar) positioned between the voltage driver and ground.The voltage control unit can be configured to have multiple states frommultiple supply rails and can receive control signals from a controller106. In a similar fashion, voltage supply units 104 ₂-104 _(N) can beelectrically coupled to actuation electrodes 102 ₁-102 _(N),respectively, as illustrated in FIGS. 1A and 1B. It should be noted thatsome actuation electrodes may not necessarily be connected to a voltagesupply unit and/or any device or component that can be configured tosupply a bias voltage to the electrode. In some embodiments, a voltagedriver can comprise a CMOS device, or any device that can be configuredto supply a bias voltage to an electrode. Furthermore, controller 106can comprise a plurality of output terminals which can be utilized tosupply control signals to voltage control units. In some embodiments,controller 106 can be configured to selectively turn on one or more ofthe voltage supply units 104 ₁-104 _(N). For example, a user can usecontroller 106 to turn on a subset of voltage supply units (e.g.,voltage supply units 104 ₂-104 ₅) while leaving the rest (e.g., voltagesupply units 104 ₁ and 104 ₆-104 _(N)) in off states (e.g., groundedstate). As such, only actuation electrodes electrically coupled tovoltage supply units 104 ₂-104 ₅ (i.e., actuation electrodes 102 ₂-102₅) will be selectively actuated, contributing to the bending ordeflecting of only part of the movable component (i.e., movable beam108) towards the first surface. Accordingly, in some embodiments,desirable static beam shapes can be achieved for better devicereliability. Furthermore, by selectively actuating and/or de-actuatingone or more of actuation electrodes 102 ₂-102 _(N), movable beam 108 canbe raised, lowered, bent, and/or curved with respect to a capacitorplate 114 in a controlled manner for obtaining specific capacitancevalues. It should be noted that the location of capacitor plate 114 asillustrated in FIG. 1A is meant to illustrate the general conceptdisclosed herein and not as a limitation, as capacitor plate 114 can beplaced anywhere on substrate 110 along the length and/or width ofmovable component 108. Furthermore, by adjusting movable beam 108 shapeand position in reference to capacitor plate 114, a wide range ofcapacitance values can be obtained. Accordingly, this configurationenables device 100 to function as a multi-state capacitor whilemaintaining a device size that is comparable to a single statecapacitor.

In some embodiments, one or more actuation plates 112 ₁ and 112 ₂ can beintegrated with movable beam 108 as illustrated in FIG. 1A. For example,actuation plate 112 ₁ can be attached to or fixed on one side of movablebeam 108 facing substrate 110. Furthermore, movable beam 108 can beanchored or connected to substrate 110 by one or more fixed anchors 120.In some embodiments, anchors 120 can be configured to include one ormore signal and/or bias paths connecting and providing controls signalsto actuation plates 112 ₁ and 112 ₂.

In some embodiments, actuation plates 112 ₁ and 112 ₂ can be partitionedinto multiple segments to include one or more capacitor electrodes.Alternatively, actuation plates 112 ₁ and 112 ₂ can be configured tohave one or more capacitive electrodes integrated and spaced apart fromcapacitor plate 114.

In some embodiments, movable beam 108 and actuation plates 112 ₁ and 112₂ can stay de-actuated (i.e., grounded). In some other embodiments,actuation plates 112 ₁ and 112 ₂ can be segmented into a plurality ofactuation electrodes electrically isolated from each other. Theplurality of actuation electrodes can be fixed to the surfaces ofmovable beam 108 and independently controlled (e.g., biased) by highvoltage drivers. For example, actuation plate 112 ₁ can be segmentedinto multiple actuation electrodes fixed to a surface on movable beam108 facing substrate 110. Each of the multiple actuation electrodes canbe independently biased by a voltage supply unit, and each voltagesupply unit can be controlled by a controller. In some embodiments, thevoltage supply unit can be controlled by controller 106, and voltagecontrol signal paths can be integrated within fixed anchors 120. Inparticular, controller 106 can be configured to control the voltagesupply units to actuate actuation electrodes in a specific manner. Forexample, a user can program controller 106 to initially actuate all theactuation electrodes. Then, a subset of actuation electrodes located ona first side of movable beam 108 can be turned off (i.e., zero bias),followed by turning off a second subset of actuation electrodes locatedon an opposing second side of movable beam 108 (or vice versa). Thisarrangement can effectively create a “rocking” motion to release movablebeam 108 from substrate 110.

FIG. 1B illustrates a side view of a second exemplary configuration of aMEMS tunable capacitor device, generally designated 140, comprisingindividual actuation electrodes according to various embodiments of thepresently disclosed subject matter. As illustrated in FIG. 1 B,capacitor device 140 can include one or more independently controllableactuation electrodes 112 ₁₁-112 _(1N) and a capacitor plate 144 fixed orattached on movable beam 108 facing substrate 110, in addition toactuation electrodes 102 ₁-102 _(N) fixed to a first surface (e.g.,substrate 110). It should be noted that it is possible that someactuation electrodes may not necessarily be connected to a voltagesupply unit and/or any device or component that can be configured tosupply a bias voltage to the electrode. In some embodiments, actuationelectrodes 112 ₁₁-112 _(1N) can be biased or actuated by a plurality ofvoltage supply units 142 ₁-142 _(N), where voltage supply unit 142 ₁-142_(N) can each include a high voltage driver (e.g., a CMOS device) and avoltage control unit (e.g., binary crowbar) positioned between thevoltage driver and ground. Specifically, for example, controller 106 canbe configured to control electrical bias voltages supplied to electrodes112 ₁₁-112 _(1N) by adjusting the bias voltages provided by voltagesupply units 142 ₁-142 _(N). Control signal paths and/or electricalconduction paths connecting controller 106 and voltage supply units 142₁-142 _(N) can be integrated within fixed anchors 120. Furthermore,electrodes 112 ₁₁-112 _(1N) fixed to substrate 110 can be actuated byvoltage supply units 104 ₁-104 _(N), also controlled by controller 106.In some embodiments, controller 106 can be configured to actuateelectrodes 112 ₁₁-112 _(1N) to bend or curve movable beam 108 into adesirable static shape, as well as for obtaining specific capacitancevalues.

In some embodiments, actuation electrodes can be selectively actuated toa high voltage state, a floating state, or a zero voltage state (i.e.,grounded state). For example, an actuation electrode (e.g., electrode102 ₃) can be set to a high voltage state (e.g., applying a bias voltageto the electrode and creating an electrostatic field) to generate anattractive force between the electrode and movable beam 108. When theattractive force is strong enough, movable beam 108 can bend and/or snapdown onto the electrode. The actuation electrode can also be configuredto a zero voltage state, for example, by grounding the electrode, andrelease movable beam 108 by effectively terminating the electrostaticfield.

In some embodiments, an actuation electrode (e.g., electrode 102 ₄) canbe selectively actuated to a floating state. For example, actuationelectrode 102 ₄ can be firstly biased with a selected high actuationvoltage (e.g., about 40 volts). A DC electrostatic field can begenerated from the actuation voltage, and movable beam 108 can be pulleddown from the beam's suspended position and come into contact withactuation electrode 102 ₄. In a transient state (e.g., while movablebeam 108 is coming down onto electrode 102 ₄), electrode 102 ₄ can beswitched to a floating state by creating an open circuit betweenelectrode 102 ₄ and voltage supply unit 104 ₄. As such, movable beam 108will come into contact with electrode 102 ₄ with less force compared toif electrode 102 ₄ was still charged with the selected high actuationvoltage. Accordingly, this configuration can improve overall devicereliability because less stress will be exerted on movable beam 108.

FIGS. 2A to 2E illustrate side views of a third exemplary configurationof a MEMS device, generally designated 100, in various actuated statesaccording to embodiments of the presently disclosed subject matter. Asillustrated in FIGS. 2A to 2E, device 100 is shown as including aplurality of independently controllable actuation electrodes 102 ₁-102₅. Although five actuation electrodes are illustrated in thisconfiguration, it should be understood that the principles discussedhere would nevertheless apply to other configurations of device 100(e.g., configurations having a greater or lesser number of actuationelectrodes). As illustrated in FIG. 2A, actuation electrodes 102 ₁-102 ₅can be fixed to a first surface (i.e., substrate 110). Movable beam 108comprising actuation plates 112 ₁ and 112 ₂ can be suspended abovesubstrate 110 and anchored or fixed to substrate 110 by one or morefixed anchor 120. When actuation electrodes 102 ₁-102 ₅ are in unbiasedstates (i.e., grounded state), movable beam 108 can remain substantiallyflat and suspended over substrate 110. Accordingly, capacitance valueunder zero bias voltage (i.e., neutral state) can be determined by thespacing 122 between electrode plate 112 ₁ and capacitor plate 114.

In some embodiments, all actuation electrodes can be actuated to a highvoltage state to assist the pull down of movable beam 108. Asillustrated in FIG. 2B, actuation electrodes 102 ₁-102 ₅ can all beactuated with a positive bias voltage to create an attractive force tocause movable beam 108 to be pulled down onto electrodes 102 ₁-102 ₅ andcapacitor plate 114. As such, this is when the capacitance value ofdevice 100 can be at its maximum (e.g., 500 fF).

In some embodiments, however, actuation of electrodes 102 ₁-102 ₅ can beselectively actuated to obtain specific capacitance values acrosselectrode plates 112 ₁ and 112 ₂ and capacitor place 114. For example,actuation electrode 102 ₁ can be biased to a zero voltage state (i.e.,grounded) to terminate the electrostatic force between electrode 102 ₁and movable beam 108. Accordingly, part of movable beam 108 can bereleased as illustrated in FIG. 2C and gap space between capacitor plate114 and movable beam 108 can be increased as a result. As such,capacitance value of tunable capacitive device 100 can be reduced (e.g.,250 fF) due to the increase of gap space between capacitor plate 114 andmovable beam 108. Similarly, as illustrated in FIG. 2D, movable beam 108can be further raised by setting actuation electrode 102 ₁ to a zerovoltage state, and capacitance value of tunable capacitive device 100can be further reduced (e.g., 125 fF).

In addition, in some embodiments, actuation electrodes 102 ₁-102 ₅ canbe selectively actuated in a sequential manner. For example, asillustrated in FIG. 2E, actuation electrodes 102 ₁-102 ₅ can firstly allbe actuated to pull down movable beam 108. Electrode 102 ₁ can bede-actuated to release part of movable beam 108 to one side of capacitorplate 114. Next, actuation electrodes 102 ₄, and 102 ₅ positioned on anopposing side of capacitor plate 114 can be de-actuated. Thisactuation/de-actuation sequence can effectively create a “rocking”motion on movable beam 108 to release movable beam 108 away fromsubstrate 110. Accordingly, less actuation voltage may be needed to pullor release movable beam 108 away from substrate 110 and as such, movablebeam 108 will experience less force during the pull away or releaseprocess and overall device reliability can be improved.

Furthermore, in some embodiments, a subset of actuation electrodes 102₁-102 ₅ can be selectively actuated to deflect movable beam 108 suchthat capacitor electrode fixed to movable beam 108 can achieve a desiredbeam shape with respect to capacitor plate 114. For example, allactuation electrodes 102 ₁-102 ₅ can be actuated during a pull-in phaseto deflect movable beam 108 toward substrate 110. Once movable beam 108is moved to a deflected position, fewer electrodes need to be actuatedto hold down movable beam 108. For example, in the configuration shownin FIGS. 2A through 2E, only electrode 102 ₁ and 102 ₂ need to beactuated to maintain a beam shape such that capacitor electrode fixed tomovable beam 108 may be optimally flattened against capacitor plate 114.This configuration not only enables device 100 to fine tune itscapacitance values, but also reduces hold down voltage and therebyincreases device reliability, because fewer actuation electrodes need tobe actuated to hold down movable beam 108.

Furthermore, in some embodiments, a subset of actuation electrodes 102₁-102 ₅ can be selectively de-actuated to improve device performance.For example, actuation electrodes 102 ₁ and 102 ₂ adjacent to andsurrounding capacitor plate 114 can be selectively de-actuated (i.e.,grounded) to act as shields against leakage currents and help preventingcapacitor plate 114 from charging. This configuration can further reducestiction between movable component 108 and actuation electrodes 102₁-102 ₅, and improve device reliability by reducing forces exerted onmovable component 108.

FIGS. 3A to 3D illustrate side views of fourth exemplary configurationof a MEMS device, generally designated 300, in various actuated statesaccording to embodiments of the presently disclosed subject matter. Forillustrative purposes, only a part of device 300 that includes actuationelectrodes 302 ₁-302 ₅ are shown in the figures. However it should benoted that the principles discussed here would nevertheless apply toalternative configurations of device 300 where actuation electrodes 302₁-302 _(N) (not shown) can be fixed to substrate 310 along the lengthand/or width of a movable component 308. As illustrated in FIG. 3A, aplurality of independently controllable actuation electrodes 302 ₁-302 ₅can be fixed to a first surface (i.e., substrate 310), movable beam 308can remain flat and suspended over substrate 310 when electrodes 302₁-302 ₅ are in a de-actuated (i.e., grounded) state. A capacitorelectrode 314 can also be fixed to substrate 310, and it should be notedthat the location of capacitor plate 314 as illustrated in FIG. 3A ismeant to illustrate the general concept and not as a limitation, ascapacitor plate 314 can be placed anywhere on substrate 310 along thelength and/or width of movable component 308. Furthermore, a standoffbump 316 can be fixed to one or more of the actuation electrodes, forexample to electrode 302 ₃ as illustrated in FIG. 3A. It should be notedthat more than one standoff bumps can be fixed to any of the actuationelectrodes, and in some embodiments, standoff bumps can also be fixed tomovable beam 308. Movable beam 308 can comprises actuation plates 318 ₁and 318 ₂ on either side of the beam. In some embodiments, actuationplates 318 ₁ and 318 ₂ can be partitioned into multiple segments toinclude one or more capacitor electrodes. Furthermore, actuation plates318 ₁ and 318 ₂ can be configured to have one or more capacitiveelectrode integrated and spaced apart from capacitor plate 314.

In some embodiments, standoff bump 316 can effectively increase anaverage distance between one or more of capacitor plate 314 and/oractuation electrodes 302 ₁-302 ₅ and movable component 308. In addition,as illustrated in FIGS. 3B to 3D, when actuation electrodes 302 ₁-302 ₅are being selectively actuated and movable component 308 is pulledtowards substrate 310, standoff bump 316 can function as a pivot tomovable component 308. For example, as illustrated in FIG. 3C, actuatingelectrode 302 ₂ can exert a force to lift a respective portion ofmovable component 308 away from actuation electrodes positioned on theother side of standoff bump 316 (e.g., actuation electrodes 302 ₄ and302 ₅). Likewise, as illustrated in FIG. 3D, actuation electrodes 302 ₄and 302 ₅ can be actuated to exert a force to lift a respective portionof movable component 308 away from actuation electrode 302 ₂ andcapacitor plate 314. This configuration can provide a number ofadvantages to the operations of device 300. For example, for high powerhot switching operations, selectively actuating electrodes aroundstandoff bump 316 can effectively increase a self-actuation releasevoltage V_(sar) for device 300. Furthermore, stiction between movablebeam 108 and actuation electrodes 302 ₁-302 ₅ can be reduced because theopening force exerted on movable beam 108 can be effectively increaseddue to pivoting. In addition, a minimum capacitance value C_(min) ofdevice 300 can be effectively lowered due to a decrease in averagedistance between actuation electrodes 302 ₁-302 ₅ and movable beam 108.

In some embodiments, antagonistic operation of actuation electrodesaround a standoff bump can be further applied to standoff pivots fixedto a surface. As illustrated in FIG. 4, a fifth exemplary configurationof a MEMS device, generally designated 400, can include one or morestandoff pivots, such as standoff pivots 412 ₁ and 412 ₂, fixed to afirst surface (i.e., substrate 404). Standoff pivots 412 ₁ and 412 ₂ canbe comparatively longer in length than standoff bump 316 (see FIGS.3A-3D) but shorter than a gap length g_(o), where g_(o) can be the gaplength between movable component 406 and actuation electrodes 410 ₁-410₄ when electrodes 410 ₁-410 ₄ are under zero biases (i.e., de-actuatedor grounded). As such, standoff pivots 412 ₁ and 412 ₂ do not come intocontact with movable component 406 when actuation electrodes 410 ₁-410 ₄are de-actuated. It should be noted that the placements of standoffpivots 412 ₁ and 412 ₂ as illustrated in FIGS. 4-6 are meant toillustrate the subject matters disclosed herein and not as a limitation.

In some embodiments, movable component 406 can include actuationelectrodes 408 ₁-408 ₃ and a capacitor plate 414. Device 400 can alsoinclude anchors 418 connecting substrate 404 and movable component 408through springs 402 and 420. It should be noted that springs 402 and 420can be substituted with other components with similar elasticity. Insome embodiments, springs 402 and 420 can be different types of springsor equivalent device components with different stiffness values. In someembodiments, actuation electrodes 410 ₁-410 ₄ and 408 ₁-408 ₃ can eachbe biased with a high voltage driver (not shown) and independentlycontrolled by a controller (not shown) with multiple output terminals.

FIG. 5 illustrates a side view of MEMS device 400 in a first actuatedstate according to embodiments of the presently disclosed subjectmatter. As illustrated in FIG. 5, actuation electrodes 410 ₂ and 410 ₃can be biased to a high voltage state and actuation electrodes 410 ₁ and410 ₄ can be configured to a zero voltage state (e.g., grounded).Accordingly, standoff pivots 412 ₁ and 412 ₂ can effectively function aspivots such that forces can be exerted to pull movable component 406down to actuation electrodes 410 ₂ and 410 ₃ and lift movable component406 away from actuation electrodes 410 ₁ and 410 ₄. As such, due to thepivoting of movable component 406 on standoff pivots 412 ₁ and 412 ₂,less actuation voltage can be used to pull movable component 406 down tosubstrate 404.

FIG. 6 illustrates a side view of MEMS device 400 in a second actuatedstate according to embodiments of the presently disclosed subjectmatter. As illustrated in FIG. 6, actuation electrodes 410 ₁ and 410 ₄can be biased to a high voltage state and actuation electrodes 410 ₂ and410 ₃ can be configured to an un-actuated and/or a zero voltage state(e.g., grounded). Accordingly, standoff pivots 412 ₁ and 412 ₂ can againeffectively function as pivots such that forces can be exerted to liftup movable component 406 away from actuation electrodes 410 ₂ and 410 ₃and pull movable component 406 down to actuation electrodes 410 ₁ and410 ₄. Accordingly, due to the pivoting of movable component 406 onstandoff pivots 412 ₁ and 412 ₂, the gap space g between fixed capacitorplate 416 and movable capacitor plate 414 can be increased to be largerthan stationary gap space g_(o), and minimum capacitance value of device400 can be lowered. Furthermore, due to the pivoting effect, an openingforce between movable component 406 and actuation electrodes 410 ₂ and410 ₃ and capacitor plate 416 can be increased, and as such,self-actuation voltage V_(sar) of device 400 can be increased andstiction due to charging or surface adhesion can be reduced oreliminated.

In some embodiments, actuator plate partitions on either side of astandoff pivot can be operated in an antagonistic manner to support acapacitance on a substrate and lid or a two-pole switch or to support anantagonistic balance for increased self-actuation voltage V_(sar). FIGS.7A to 7C illustrate a sixth exemplary configuration for a MEMS device,generally designated 700, including a first surface (i.e., substrate702) spaced apart from a second surface (i.e., lid 704) and a movablecomponent 716 positioned there between (i.e., suspended betweensubstrate 702 and lid 704). Device 700 can further include standoffpivots extending from one or more of substrate 702, lid 704, and/ormovable component 716. In the particular configuration illustrated inFIGS. 7A through 7C, for example, a first set of standoff pivots 708 ₁and 708 ₂ is fixed to substrate 702, and a second set of standoff pivots708 ₃ and 708 ₄ is fixed to substrate lid 704. A capacitor plate 718 canbe fixed to substrate 702, another capacitor plate 712 can be fixed tolid 704, and yet another capacitor plate 720 can be fixed to movablecomponent 716. Device 700 can further include a plurality of actuatorplates partitioned into a plurality of actuation electrodes with variousdimensions fixed to one or more surfaces. For example, a first pluralityof actuation electrodes 710 ₁-710 ₄ can be fixed to substrate 702 and asecond plurality of actuation electrodes 722 ₁-722 ₃ can be fixed tomovable component 716. It should be noted that the exact number ofactuation electrodes as illustrated in FIGS. 7A to 7C are meant toillustrate the subject matter disclosed herein and not as a limitation.Two fixed anchors 724 can be positioned between substrate 702 and lid704, and movable component 716 can be anchored or fixed to one or moreof anchors 724 through two springs 706 and 714. It should be noted thatsprings 706 and 714 can have different stiffness values and can bereplaced by other functional equivalent device components or structures.

In some embodiments, as illustrated in FIG. 7A, actuation electrodes 710₁and 710 ₄ can be biased to a high voltage state and actuationelectrodes 710 ₂ and 710 ₃ can be configured to a zero voltage state(e.g., grounded). Furthermore, actuation electrode 722 ₃ may bepartitioned into multiple segments to include one or more capacitorelectrodes. Alternatively, actuation plate 722 ₃ can be configured tohave one or more capacitive electrode integrated and spaced apart fromcapacitor plate 712. Accordingly, standoff pivots 708 ₁ through 708 ₄can effectively function as pivots such that forces can be exerted tolift up movable component 716 away from actuation electrodes 710 ₂ and710 ₃ and capacitor plate 718 and pull movable component 716 down toactuation electrodes 710 ₁ and 710 ₄. Accordingly, due to the pivotingof movable component 716 on standoff pivots 708 ₁ through 708 ₄ asillustrated in FIG. 7A, because not every actuation electrode needs tobe actuated, less actuation voltage may be needed to lift movablecomponent 716 away from capacitor plate 718 and closer to capacitorplate 712.

Furthermore, as illustrated in FIG. 7C, actuation electrodes 710 ₂ and710 ₃ can be biased to a high voltage state and actuation electrodes 710₁ and 710 ₄ can be configured to a zero voltage state (e.g., grounded).Accordingly, standoff pivots 708 ₁ through 708 ₄ can again effectivelyfunction as pivots such that forces can be exerted to lift up movablecomponent 716 away from actuation electrodes 710 ₁ and 710 ₄ and pullmovable component 716 down to actuation electrodes 710 ₂ and 710 ₃.Accordingly, due to the pivoting of movable component 716 on standoffpivots 708 ₁ through 708 ₄, not every actuation electrode within device700 needs to be actuated to bring movable component 716 closer tocapacitor plate 718 and away from capacitor plate 712. As such, asillustrated in FIGS. 7A to 7C, selectively actuating actuationelectrodes 710 ₁-710 ₄ around standoff pivots 708 ₁-708 ₄ can causemovable component 716 to deflect between capacitor plate 718 and 712,effectively increase the capacitance tuning range of device 700 comparedto a two plated system. Furthermore, due to the pivoting effect, anopening force between movable component 716 and capacitor plates 712,718 can be increased, and as such, self-actuation voltage V_(sar) can beincreased and stiction due to charging or surface adhesion can bereduced or eliminated.

In some embodiments, further actuation electrodes can be fixed to asecond surface to assist the deflection and/or movement of a movablecomponent. FIGS. 8A to 8C illustrate a seventh exemplary configurationof a MEMS device, generally designated 800, with actuation electrodes812 ₁-812 ₄ fixed to a second surface (i.e., lid 804). Similar to otherembodiments previously presented, a movable component 818 can bepositioned between a first surface (i.e., substrate 802) and a secondsurface (i.e., lid 804) and connected to two fixed anchors by springs806 and 820. In addition to actuation electrodes 814 ₁-814 ₄ fixed to afirst surface (i.e., substrate 802), actuation electrodes 812 ₁-812 ₄can also be selectively actuated to assist the deflection of movablecomponent 818. For example, as illustrated in FIG. 8A, in addition toactuation electrodes 814 ₁ and 814 ₄, actuation electrodes 812 ₂ and 812₃ can also be actuated to pull movable component 818 toward capacitorplate 822. Under this actuation configuration, actuation electrodes 814₂ and 814 ₃ can be de-actuated (e.g., grounded) and standoff pivots 816₁-816 ₄ can pivot movable component 818 away from capacitor plate 824and towards capacitor plate 822. Similarly, as illustrated in FIG. 8C,in addition to actuation electrodes 814 ₂ and 814 ₃, actuationelectrodes 812 ₁ and 812 ₄ can also be selectively actuated to a highvoltage state to deflect movable component 818 towards capacitor plate824. Under both actuated states (as illustrated in FIGS. 8A and 8C),pivoting around standoff pivots 816 ₁-816 ₄ causes an increase of anopening force to bend or deflect movable component 818 between capacitorplates 822 and 824. Accordingly, such configuration can effectivelyincrease a self-actuation voltage V_(sar) of device 800 and stiction dueto charging or surface adhesion can be reduced or eliminated.

In some embodiments, one or more standoff bumps can be attached to amovable component to further reduce stiction due to charging or surfaceadhesion. As illustrated in FIGS. 9A to 9C, an eight exemplaryconfiguration of a MEMS device, generally designated 900, is provided.In such a configuration, standoff bumps 912 can be attached to movablecomponent 918. For example, standoff bumps 912 can be fixed to capacitorplate 910 and/or actuation plate 908 ₁. Furthermore, similar to otherembodiments previously presented, a movable component 918 can bepositioned between a first surface (i.e., substrate 902) and a secondsurface (i.e., lid 904) and connected to two fixed anchors by springs906 and 922. Standoff pivots 9161 and 9162 can be fixed to substrate 902and standoff pivots 916 ₁ and 916 ₂ can be fixed to lid 904. In someembodiments, actuation plate 908 ₁ can be partitioned into multiplesegments to include one or more capacitor electrodes. Alternatively,actuation plate 908 ₁ can be configured to include one or morecapacitive electrodes integrated and spaced apart from capacitor plate924 fixed to a second surface (i.e., lid 904).

As illustrated in FIG. 9B, under a neutral state (i.e., un-actuated orun-biased state), standoff bumps 912 would not come in contact withcapacitor plates 924 and 926. However, when actuation electrodes 914 ₁,914 ₄, 920 ₂, and 920 ₃ are actuated, movable component 918 can bepulled toward capacitor plate 924. As illustrated in FIG. 9A, standoffbumps 912 fixed to a capacitor region on actuation electrode 908 ₁ canprevent capacitor plate 924 from come into direct contact with actuationelectrode 908 ₁, thereby reducing or eliminating stiction due to surfaceadhesion. Similarly, as illustrated in FIG. 9C, standoff bumps 912 fixedto capacitor plate 910 can prevent capacitor plate 926 from come intodirect contact with capacitor plate 910, when actuation electrodes 914 ₂and 914 ₃ and actuation electrodes 920 ₁ and 920 ₄ are actuated (i.e.,high voltage state) and movable component 918 is pulled toward capacitorplate 926. This configuration can advantageously increase aself-actuation voltage V_(sar) for device 900 and stiction due tosurface adhesion can be reduced or eliminated.

The present subject matter can be embodied in other forms withoutdeparture from the spirit and essential characteristics thereof. Theembodiments described therefore are to be considered in all respects asillustrative and not restrictive. Although the present subject matterhas been described in terms of certain preferred embodiments, otherembodiments that are apparent to those of ordinary skill in the art arealso within the scope of the present subject matter.

What is claimed is:
 1. A micro-electro-mechanical system (MEMS) devicecomprising: a first plurality of fixed actuation electrodes attached toa first surface; a second plurality of fixed actuation electrodesattached to a second surface that is spaced apart from the firstsurface; at least one actuation electrode attached to a movablecomponent; and two or more independently controllable driver circuits,each independently controllable driver circuit connected to at least onecorresponding fixed actuation electrode of the first plurality of fixedactuation electrodes or the second plurality of fixed actuationelectrodes and the two or more independently controllable drivercircuits being configured to control an electric charge applied to theat least one corresponding fixed actuation electrode; wherein themovable component is positioned between the first surface and the secondsurface and is movable with respect to the first or second surface. 2.The MEMS device of claim 1 further comprising at least one fixedcapacitor plate fixed to one or both of the first and second surfacesand spaced apart from at least one movable capacitive electrode fixed tothe movable component.
 3. The MEMS device of claim 2, wherein the firstand second plurality of fixed actuation electrodes are selectivelycontrollable to deflect the movable component relative to the first orsecond surface to any of a plurality of positions corresponding to aplurality of capacitance states of the at least one fixed capacitorplate and the at least one movable capacitive electrode.
 4. The MEMSdevice of claim 1, comprising one or more standoff pivots attached toone of the first or second surfaces or the movable component, whereinactuation of one or more of the first or second plurality of fixedactuation electrodes positioned on one side of one of the one or morestandoff pivot can cause a portion of the movable component on anopposing side of the standoff pivot to deflect away from the first orsecond surface.
 5. The MEMS device of claim 1, wherein the movablecomponent is connected to the first and second surface by at least onespring.
 6. The MEMS device of claim 1 further comprising a plurality ofindependently-controllable voltage drivers each connected to one of theplurality of actuation electrodes.
 7. The MEMS device of claim 1 furthercomprising at least one standoff bump attached to the movable component,wherein the at least one standoff bump is configured to prevent contactbetween at least a first portion of the first plurality of actuationelectrodes and at least a second portion of the movable component or toprevent contact between at least a third portion of the second pluralityof actuation electrodes and at least a fourth portion of the movablecomponent.
 8. The MEMS device of claim 1, wherein the movable componentis connected to the first surface and the second surface by at least onefixed anchor.
 9. A micro-electro-mechanical system (MEMS) devicecomprising: a plurality of fixed actuation electrodes attached to afirst surface, wherein each of the plurality of fixed actuationelectrodes is independently controllable; a fixed capacitor plate fixedto the first surface; a movable component spaced apart from the firstsurface and movable with respect to the first surface, the movablecomponent comprising one or more movable actuation electrodes spacedapart from the plurality of fixed actuation electrodes and a movablecapacitor electrode spaced from the fixed capacitor plate; a controllerin communication with the plurality of fixed actuation electrodes andthe plurality of movable actuation electrodes and configured toselectively actuate a first number of the plurality of actuationelectrodes during a pull-in phase to deflect the movable componenttowards the first surface and to de-actuate one or more of the firstnumber of the plurality of actuation electrodes while maintaining themovable component in a deflected position during a hold down phase,wherein a second number of the plurality of actuation electrodes that isless than the first number remains actuated during the hold down phaseto adjust a shape of the movable component such that the movablecapacitor electrode is optimally flattened to maximize a capacitancebetween the movable capacitor electrode and the fixed capacitor plate inthe hold down phase; and at least one standoff bump attached to at leastone of the plurality of actuation electrodes, wherein the at least onestandoff bump is configured to prevent contact between at least a firstportion of the actuation electrodes and at least a second portion of themovable component.
 10. A method for adjusting a shape of a movablecomponent of a micro-electro-mechanical system (MEMS) device comprising:in a first directional phase, deflecting the movable component towards afirst surface by selectively actuating a first combination of fixedactuation electrodes selected from either or both of a first pluralityof fixed actuation electrodes or a second plurality of fixed actuationelectrodes using one or more independently controllable voltage driver;and in a second directional phase, deflecting the movable componenttowards a second surface by selectively actuating a second combinationof fixed actuation electrodes selected from either or both of the firstplurality of fixed actuation electrodes or the second plurality of fixedactuation electrodes using one or more independently controllablevoltage driver; wherein a movable capacitor electrode is attached to themovable component and a first fixed capacitor plate is fixed to thefirst surface.
 11. The method of claim 10 further comprising: whereindeflecting the movable component towards the first surface comprisesselectively actuating a first number of the first combination of fixedactuation electrodes; wherein the method further comprises, at the endof the first directional phase, selectively de-actuating one or more ofthe first number of the first combination of fixed actuation electrodeswhile maintaining the movable component in a deflected position, whereina second number of the first combination of fixed actuation electrodesthat is less than the first number remain actuated after selectivelyde-actuating the one or more of the first number of the firstcombination of fixed actuation electrodes to adjust a shape of themovable component; wherein deflecting the movable component towards thesecond surface comprises selectively actuating a third number of thesecond combination of fixed actuation electrodes; and wherein the methodfurther comprises, at the end of the second directional phase,selectively de-actuating one or more of the third number of the secondcombination of fixed actuation electrodes while maintaining the movablecomponent in a deflected position, wherein a fourth number of the secondcombination of fixed actuation electrodes that is less than the thirdnumber remain actuated after selectively de-actuating the one or more ofthe third number of the second combination of fixed actuation electrodesto adjust the shape of the movable component.
 12. The method of claim11, wherein selectively de-actuating one or more of the first number ofthe first combination of fixed actuation electrodes comprisesselectively grounding at least one of the first number of the firstcombination of fixed actuation electrodes.
 13. The method of claim 10,wherein adjusting the shape of the movable component comprisesdeflecting the movable component into a shape such that the movablecapacitor electrode is optimally flattened to maximize a capacitancebetween the movable capacitor electrode and the first fixed capacitorplate.
 14. The method of claim 10, wherein a second fixed capacitorplate is fixed to the second surface.
 15. The method of claim 14,wherein adjusting the shape of the movable component comprises changinga first spacing between the movable capacitor electrode and the firstfixed capacitor plate or a second spacing between the movable capacitorelectrode and the second fixed capacitor plate.
 16. The method of claim10, wherein the first combination of fixed actuation electrodescomprises one or more electrodes attached to the first surface and oneor more electrodes attached to the second surface.
 17. The method ofclaim 10, wherein the second combination of fixed actuation electrodescomprises one or more electrodes attached to the first surface and oneor more electrodes attached to the second surface.
 18. The method ofclaim 10 further comprising: in the first directional phase, selectivelyde-actuating one or more of the second combination of fixed actuationelectrodes that are actuated.
 19. The method of claim 10 furthercomprising: in the second directional phase, selectively de-actuatingone or more of the first combination of fixed actuation electrodes thatare actuated.
 20. The method of claim 10, wherein the first plurality offixed actuation electrodes is independently controllable and attached tothe first surface; and wherein the second plurality of fixed actuationelectrodes is independently controllable and attached to the secondsurface.